Catalytic conversion of hydrocarbons



J.- R. WILSON CATALYTIG coNvERsIQN oFv HYDBOGARBONS July 22, 1941.

Filed Nov. 22, 1937 m S .d Y. w n n2/Vm 4.www O ww n NM1 man. A. 9.502%@ SY u @E Nma Patentedl J ul-y 1.941

yUNITED STATES." PATENT o1-F1os Jesse Russell Wilson, Chicago, Ill., assig'nor .to- Standard Oil Company, Chicago, lll., a corporation of Indiana Application November 22, 1937, serial No. 175,s1s'

(o1. 19e-s)- Claims.

- This invention relates to a process of convert` ing hydrocarbons into motor fuels wherein .hydrocarbons heavier than gasoline are simultaneously converted with hydrocarbonslighter than gasoline to produce hydrocarbons boiling within the gasoline boiling range, which may be defined as an initial boiling point of about 80 to 120 F. and a final boiling point of about 350 to 450 F. One object oi the invention is to facilitate the interaction of normally gaseous hydrocarbons such as ethane, propane and butane, ethylene, propylene and butylene with gas oil and its decomposition products.

Another object of the invention is to simultaneously convert hydrocarbon gases having a relatively high hydrogen to carbon ratio and end thereof gas oil preheated to cracking temcatalyst to the desired-conversion temperature,

an operation which is beset with many difiiculties. Other objects of the invention will be apparent 'from the following description.

The drawing which forms a part of this specification illustrates diagrammatically apparatus heavy oils, thereby producing a larger yield of gasoline with a smaller production of carbonaceous matter, coke, asphalt, etc. By carrying out the reaction in the presence of a catalyst I am also enabled to produce a gasoline having a high knock rating. For example, instead of obtaining a gasoline having a knock rating of 65 to 70 octane number from Mid-Continent gas oil,

I am enabled to produce a gasoline having an octane number of between '75 and 90 as a result of the speciiic effect of the catalyst in rearranging the structure of the heavy hydrocarbons by 'interaction with the normally gaseous-hydrocarbons which I employ. y

In all catalytic conversion processes employed heretofore great difficulty has been encountered with the deposition of carbonaceous matter, coke, etc. on the catalyst, rapidly rendering it inactive. Various devices have been employed to overcome this difliculty, such as burning oil the carbonaceous matter at `intervals lwithout removing it from the catalyst chamber. An object of my invention is to employ the catalyst in a fine state of subdivision and maintain it continuously in a liquid slurry throughout the process, in which form the catalyst iskpumpable and may be continuously introduced into the conversion zone and withdrawn therefrom after it has lost' its actlvitv. Another object of my invention is to conduct the conversion reaction under such conditions that substantially only the high boiling asphaltic oils produced in the process are discharged with the catalyst from the conversion chamber and this object is accomplished by regulating the temperature and introduction of the hydrocarbon gas stream entering the confor carrying out the process wherein gas oil and gases are separately heated and discharged into a conversion chamber in contact with a continuI ous stream of dispersed catalyst, after which the productsare separated and partly recycled. Re-

ferring to the drawing, -gas oil, for example straight-run Pennsylvania or Mid-'Continent gas oil, is introduced by line Ill vand pump i I to pipe heater I2 wherein it is heated to a temperature above the cracking temperature, for, example S-900 F., or 950 F. Under these conditions about 10 to 25% of the gas oil may be converted to gasoline. The stream of hot gas oil and gas oil vapors is'conducted under high pressure by line I3 to conversion chamber I4, the stream entering the tower near the upper end thereof. Tower I4 is provided with suitable baille plates or other contact means such as bubble plates which provide an extended surface for contact between liquid and vapor, permitting the liquid to flow without obstruction to the bottom of the tower and permitting the vapor and gases in the tower to iiow tothe tcp thereof and escape by vapor lineV l5 leading to i'ractionating tower I8 where the vapors and gases are fractionated to separate therefrom constituents heavier than gasoline which are withdrawn as a reflux by line f tionated therefrom and withdrawn by line 20 version chamber. Still another object of my inventlon is to control the temperature of the conversion chamber by introducing at the upper leading'to condenser 2i and receiver 22 wherein the 3 and 4 carbon hydrocarbons are condensed with some` ethane and ethylene. IUncondensed gases are discharged by line 23. A portion of the condensate is withdrawn by pump 24 and recy-x cled by line 25 to the upper part of stabilizer I9 as a reux. The remainder is recycled vto the f process asv hereinaftervdescribed. The gasoline produced in the process, now having the desired 1100 F. in some cases.

-initial and final boiling points, is withdrawn by line 2l.

Now returning to the conversion chamber Il. a slurry of catalyst is introduced at the upper part thereof by 1lne 21 through which the slurry is forced by pump 23, taking suction on mixer 28. Mixer 29 is supplied by a stream of gas oil through valved line 30 or by a stream of cycle oil to valve line 3l as desired. When employing cycle oil for mixing the slurry I prefer to withdraw it directly from line I1 without cooling, thus providing a slurry which is relatively hot and which therefore produces a minimum amount of cooling in the top of the conversion chamber I '4. Catalyst for making slurry is introduced in the form of a powder through hopper 32. The catalyst may be nely divided fullers earth, bentonite, Attapulgus clay fines, Death Valley clay, etc. and I find that the catalytic activity of some of these clays, for example the bentonite may be considerably increased by ini` tially acid treating them in a manner known to the art. Said treatment may be carried out with phosphoric acid and a small amount of acid may be allowed to remain on the clay which is then dried before mixing with the oil in mixer 29. I may also employ finely divided bauxite, aluminum silicate, boron silicate, etc.

The catalyst slurry which may contain about 25 to 50% of catalyst carried in the oil with which it is mixed is preferably introduced at a higher point in the tower than the point of introduction of the hot gas oil stream from line I3, thus providing a reuxing action and preventing undesirable entrainment of partially cracked products in the vapors discharged through line I5. For this purpose I prefer to employ several bubble plates above the point of admission of the hot gas oil vapors. The slurry of catalyst descends through the tower Il over the baille plates therein provided and is' intimately contacted with the gas oil, the unvaporized portions of which also ow downward through the tower with the catalyst. The

' amount of catalyst slurry introduced may be In the downward passage through the tower f the catalyst and oil come in contact with a stream of gas passing upward through the tower from gas inlet line 33. Gas required for the process is obtained partly from external sources and partly by recycling Within the system as hereinafter described. Externally provided gas which may suitably consist of the 2, 3, and 4 carbon hydrocarbons is introduced'by line 3l and compressor 3l to heater 36 where the temperature -is raised to a high temperature, for example to 900, 950, or 1000 F. and even to A't these temperatures the gas may be partially desaturated in passing through the heater with the result that the gas supplied to the conversion chamber by line 33 contains a considerable proportion of olens, e. g., abouty 30 to 50%, and as high as 60% in some cases. Oleiins are particularly desired for the process because of the greater facility with which they react with the oil and`because of the exothermic nature of this reaction which assists in maintaining the temperature of the conversion chamber within the desired reaction range. The temperature of the gas, however. may be varied to'control the degree of evaporation of oil in in conversion chamber I 4 and maintain a liquid phase throughout the chamber as a medium for supporting and transferring the dispersed catalyst I prefer to employ a high pressure in the system. The high pressure is also advantageous in operating the fractionating tower IB and stabilizer I9, Yalthough the pressure maintained in towers I3 and I9 may suitably be reduced below the pressure of the conversion chamber by pressure reducing valve 39 in line I5. I prefer to maintain a pressure in chamber I4 of only slightly below the critical pressure of the heavy oil withdrawn at the base thereof. 'I'hus I may suitably employ pressures of 500 to 1000 lbs. per sq. in. in the chamber Il, although somewhat lower pressures may be employed, for example 200 to 400lbs. per sq. inch. When lower pressures are employed it is necessary to operate at a correspondingly lower temperature, thus decreasing the conversion rate and reducing the capacity of the unit. I prefer to employ presf sures of the order of 200 to 400 lbs. per sq. in.

in fractionator tower I6 and stabilizer I 9. The oil withdrawn from the base of the tower is comprised principally of 'high boiling asphaltic reaction products of the process, together with so'me gas oil dissolved therein. It is withdrawn by line 40 and forced through filter 4I wherein the oil is removed from the catalyst, the catalyst 'being discharged by conveyor I2 and the oil by line 43 leading to tar flash chamber 44. The pressure having been reduced in filter 4I and valve 45, distillate is removed from the tar in 44 by line i6 leading to condenser 41 and receiver 48. I may also employ subatmospheric pressures on tar chamber 44 to increase the recovery of hydrocarbons from the tar and reduce the tar gravity. The products thus separated may be conducted by pump 49 and line 50 to fractionating tower I6, previously described. Tar is withdrawn from the base of tower 44 by line 5I. The catalyst which is withdrawn' from the filter 4I by conveyor 42 is preferably conducted to a reburning furnace (not shown) wherein the carbonaceous matter with which it is impregnated is destroyed, leaving the catalyst in an active condition for reuse in the process.

vOne of the unique advantages of my process arising from the countercurrent treatment of the gas oil and gas ls the greater conversion of gases, especially the saturated gases. Fresh catalyst contacts the gases as .they are leaving the conversion zone, thus exerting the maximum action thereon. Later, when the catalyst is becoming exhausted, it contacts the more unsaturated and hotter gases, all in the presence of heavy oil, thereby obtaining maximum catalyst utilization.

Although I have described my process with respect to a specific example ther of, I intend that it be limited only by the following claims.

hydrocarbons into gasoline, which comprises heating the heavy hydrocarbon oil to a cracking temperature, introducing the heated oil into the upper part of an elongated, vertically disposed conversion zone, introducing a dispersed contact catalyst solid at the' temperature employed into the heated oil near the point of introduction into said zone, allowing the catalyst and heated oil to mingle and descend through said conversion zone, heating said hydrocarbon gas above said cracking temperature and introducing it into the lower part oi said conversion zone, regulating temperature and pressure to maintain said oil in the liquid phase and effecting a conversion reaction between said heated hydrocarbon gas and said oil counteriowing in said conversion zone in contact with said catalyst whereby a high knock rating gasoline is produced.

2. In the process of claim 1 withdrawing the reaction products formed within said conversion zone and fractionating them to separate therefrom gas, gasoline and heavier cycle oil, heating said cycle oil and returning it to the upper portion of said conversion zone. condensing a portion of the gas under pressure,heating said condensed portion above said cracking temperature and returning it to the lower part of said conversion lzone and withdrawing gasoline from the process.

3. The process oi claim 1 wherein the oil descending in the conversion zone with the catalyst is largely but not entirely evaporated by the hot gas introduced therein and the catalyst `suspended in unevaporated asphalt is withdrawn from the conversion zone, is illtered to remove the catalyst from the asphalt and the resulting catalyst-free asphalt is evaporated to recover a distillate andsaid distillate is returned to the conversion system.

4. The process 'of continuously converting heavy hydrocarbon oils and gases to gasoline without the necessity of periodically stopping' the `from the'reaction zone.

5. The process of converting` hydrocarbon gases f and heavy oils to gasoline which comprises sub iecting the said hydrocarbon gases to a high temperature suiilcient to convert saturated constituents thereof into oleiins. subjecting a heavy oil to a cracking temperature and partly converting process to remove coke from the reaction vessels,

it into gasoline, unsaturated gases and high boiling asphaltic products, introducing said heated oil and a dispersed contact catalyst solid at the temperature employed into the upper section of a contact conversion zone, introducing said heated gas into the lower' section o said contact conversion zone, passing said gas upward through said contact conversion zone in countercurrent contact with said oil and catalyst'whereby said gas is caused to react with said oil to produce gasoline, withdrawing the vapors of gasoline and said gas from the upper section 0i said contact conversion zone, subjecting said vapors to fractionation to produce gas, gasoline and heavy recycle oil, recycling said heavy recycle oil and said gas to said contact conversion zone. and withdrawing a slurry of said asphaltic products and spent catalyst irom the lower section oi said contact conversion zone.

6. The process of claim 5 wherein the spent catalyst is separated from the asphaltic products and thereafter reviviiied and recycled to the process.

7. In the process oi' converting a heavy hydrocarbon oil to gasolineby contacting it` at a high conversion temperature with a ilnely divided contact catalyst solid at the temperature employed wherein the heat required for the reaction is introducedjinto the oil prior to contact with the catalyst and the reaction mixture suffers an undesirable loss in temperature because of the endothermic nature of the cracking reaction, the improvementcomprsing heating said heavy hydrocarbon oil and introducing it into a conversion zone, introducing a stream of nely I divided catalyst into said zone at a point near the point of introduction of said oil, and maintaining the desired conversion temperature by introducing a stream'of heated unsaturated'hydrocarbon gas to flow countercurrent to said reaction mixture at a high pressure whereby the hydrocarbon gas is caused to react exothermically with the oil in the presence of said catalyst.

8. The process of converting a heavy hydrocarbon oil into high knock rating gasoline by heating at elevated temperatures and in the.

presence of catalysts, comprising heating said oil to cracking temperature and passing it downward through an elongated reaction zone concurrently and in intimate contact with a finely divided catalyst which is solid at the reaction temperature employed, passing an unsaturated hydrocarbon gas upward through said reaction zone regulating temperature and pressure to maintain a liquid phase in said reaction zone and supplying sufllcient heat to said gas prior to its introduction to said reaction zone to maintain the desired cracking temperature therein.

9. The process of claim 8 wherein the temperature and amount of said gas introduced into said reaction zone are controlled to prevent completo vaporization of said oil in said reaction zone.

10. The process of claim 9 wherein said reaction zone is maintained under a pressure of about 200 to about 1000 lbs. per square inch.

JESSE RUSSELL WILSON.

. CERTIFICATE op CORRECTION. Patent No. 2,21I9,92LL.- July 22, 19m.

' 'JESSE RUSSELL wI'LsoN'.

I-t ,is hereby Certified that error appears in the printed specification of theabeve numbered patent requiring correctionas follows: Page 5, .sec-

10nd celumm; line 65, claim 10, for the claim refe-rence numeral "9" read -8'; and that the said Letters Patent'should be read with` this correction-therein that the vsame'may conform to the record ef the case in the PatentA office.. A

Signed saale@ ths 2nd day of September, A. D; 19141.

Henry Van Arsdle, (Seal) Acting Commissioner of Patents. 

